US8680226B1ActiveUtility

Method for alcoholysis of acrylonitrile-butadiene-styrene-containing polycarbonate compositions

85
Assignee: SAUDI BASIC IND CORPPriority: Dec 21, 2012Filed: Dec 21, 2012Granted: Mar 25, 2014
Est. expiryDec 21, 2032(~6.5 yrs left)· nominal 20-yr term from priority
Inventors:Philip Wesley BellAlexander StanislausVenkata Ramanarayanan Ganapathy BhotlaTukaram GunaleDarshan Jayanna
C08L 55/02Y02W30/62C08L 69/00C08J 2369/00C08J 2455/02C08J 11/24
85
PatentIndex Score
5
Cited by
20
References
30
Claims

Abstract

The disclosure provides a method for recovering a dihydroxy aromatic compound and a dialkyl carbonate from a polycarbonate-containing composition comprising a polycarbonate and acrylonitrile-butadiene-styrene. The method comprises heating the composition in the presence of an alcohol and a transesterification catalyst at a temperature of 70° C. to 200° C. and a pressure of 50 mbar to 40 bar in a reactor for a time sufficient to depolymerize the polycarbonate producing a dihydroxy aromatic compound and a dialkyl carbonate; removing the dihydroxy aromatic compound and the dialkyl carbonate from the reactor, the acrylonitrile-butadiene-styrene remaining as a coating on the surfaces of the reactor; adding a solvent to the reactor; and heating the solvent to remove the acrylonitrile-butadiene-styrene from the surfaces of the reactor.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A method for recovering a dihydroxy aromatic compound and a dialkyl carbonate from a polycarbonate-containing composition comprising a polycarbonate and acrylonitrile-butadiene-styrene, the method comprising
 heating the composition in the presence of an alcohol and a transesterification catalyst at a temperature of 70° C. to 200° C. and a pressure of 50 mbar to 40 bar in a reactor for a time sufficient to depolymerize the polycarbonate, producing a dihydroxy aromatic compound and a dialkyl carbonate; 
 removing the dihydroxy aromatic compound and the dialkyl carbonate from the reactor, the acrylonitrile-butadiene-styrene remaining as a coating on the surfaces of the reactor; 
 adding a solvent to the reactor; and 
 heating the solvent to remove the acrylonitrile-butadiene-styrene from the surfaces of the reactor. 
 
     
     
       2. The method of  claim 1 , wherein the solvent is a polar aprotic solvent. 
     
     
       3. The method of  claim 1 , wherein the solvent is acetone, ethyl acetate, methyl ethyl ketone, trichloromethane dichloromethane, acetonitrile, methyl isobutyl ketone, or a combination comprising at least one of the foregoing. 
     
     
       4. The method of  claim 1  further comprising separating a blend of the alcohol and the dialkyl carbonate from the dihydroxy aromatic compound by distillation. 
     
     
       5. The method of  claim 1 , wherein the alcohol is a C 1-10  alcohol. 
     
     
       6. The method of  claim 5 , wherein the alcohol is methanol. 
     
     
       7. The method of  claim 1 , wherein the polycarbonate is a bisphenol A polycarbonate, the alcohol is methanol, the dihydric phenol is bisphenol A, and the dialkyl carbonate is dimethyl carbonate. 
     
     
       8. The method of  claim 1 , wherein the polycarbonate-containing composition comprises a phosphorus-containing flame retardant. 
     
     
       9. The method of  claim 8 , wherein the flame retardant is bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), or a combination thereof. 
     
     
       10. The method of  claim 1 , wherein the catalyst is a tin compound, a zinc compound, a titanium compound, an aluminum compound, or a combination comprising at least one of the foregoing. 
     
     
       11. The method of  claim 1 , wherein the catalyst is tetra(isopropyl)titanate, dibutyltin oxide, aluminum isopropoxide, a metal phenoxide, or a combination comprising at least one of the foregoing. 
     
     
       12. The method of  claim 1 , wherein the catalyst is a catalyst purge stream from a diphenyl carbonate product unit. 
     
     
       13. The method of  claim 1 , wherein the catalyst is a titanium-based catalyst, and wherein the method further comprises removing the catalyst by adding a sufficient amount of water to a blend of dihydroxy aromatic compound, the dialkyl compound and the alcohol to convert the catalyst to titanium dioxide and filtering to remove titanium dioxide. 
     
     
       14. The method of  claim 1 , wherein the catalyst is present in an amount of 0.01 wt % to 4 wt % based upon the total weight of the polycarbonate-containing composition and the alcohol. 
     
     
       15. The method of  claim 1 , wherein the catalyst is present in an amount of 0.01 wt % to 2 wt % based upon the total weight of the polycarbonate-containing composition and the alcohol. 
     
     
       16. The method of  claim 1 , wherein the alcohol is present in an amount of 200 weight percent to 600 weight percent based upon the weight of polycarbonate-containing composition. 
     
     
       17. The method of  claim 1 , wherein the alcohol is added as a methanol stream comprising from 0 to 50 weight percent dimethyl carbonate. 
     
     
       18. The method of  claim 1 , wherein the alcohol is ethanol or n-butanol. 
     
     
       19. The method of  claim 18 , wherein the dialkyl carbonate is diethyl carbonate or dibutyl carbonate. 
     
     
       20. A method for the manufacture of a polycarbonate comprising
 separating the dihydroxy aromatic compound from the dialkyl compound of  claim 1 ; and 
 polymerizing the dihydroxy aromatic compound and a carbonyl source to provide the polycarbonate. 
 
     
     
       21. The method of  claim 20 , wherein the solvent is a polar aprotic solvent. 
     
     
       22. The method of  claim 20 , wherein the solvent is acetone, ethyl acetate, methyl ethyl ketone, trichloromethane dichloromethane, acetonitrile, methyl isobutyl ketone, or a combination comprising at least one of the foregoing. 
     
     
       23. A method for the manufacture of diphenyl carbonate comprising
 separating the dihydroxy aromatic compound from the dialkyl carbonate of  claim 1 ; and 
 reacting the dialkyl carbonate with phenol to provide diphenyl carbonate. 
 
     
     
       24. The method of  claim 23 , wherein the solvent is a polar aprotic solvent. 
     
     
       25. The method of  claim 23 , wherein the solvent is acetone, ethyl acetate, methyl ethyl ketone, trichloromethane dichloromethane, acetonitrile, methyl isobutyl ketone, or a combination comprising at least one of the foregoing. 
     
     
       26. A method to manufacture a polycarbonate composition comprising
 separating the dihydroxy aromatic compound from the dialkyl compound of  claim 1 ; 
 reacting the dialkyl carbonate with phenol to provide diphenyl carbonate; and 
 polymerizing the dihydroxy aromatic compound and diphenyl carbonate to provide the polycarbonate composition. 
 
     
     
       27. The method of  claim 26 , wherein the solvent is a polar aprotic solvent. 
     
     
       28. The method of  claim 26 , wherein the solvent is acetone, ethyl acetate, methyl ethyl ketone, trichloromethane dichloromethane, acetonitrile, methyl isobutyl ketone, or a combination comprising at least one of the foregoing. 
     
     
       29. A polycarbonate manufactured by the method of  claim 20 . 
     
     
       30. A polycarbonate manufactured by the method of  claim 26 .

Cited by (0)

No later patents cite this yet.

References (0)

No backward citations on record.